Diagnostic Functions Additional Heater 912-B
Overview
General
The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors itself and the input and output signals.
Caution! To communicate with parking heater 912B installed in cars with chassis numbers to 314999 inclusive and in cars with chassis numbers 315000 and later where the early heater unit (30863852) is installed, a special diagnostic cable 951 1520 Diagnostic lead 951 1520 Diagnostic Lead must be used. In certain cars communication with the parking heater cannot be established when the ignition is switched on because of the absence of +15 voltage supply. To communicate with this type of heater it must be started or an attempt to start it must be made using the timer. Single components and functions cannot be activated when the +15 voltage supply is absent.
Diagnostic trouble codes (DTCs)
The control module will store a diagnostic trouble code (DTC) if it detects a fault. The control module can store up to 25 diagnostic trouble codes (DTCs).
If a fault disappears for any reason after the diagnostic trouble code (DTC) has been permanently stored in the control module, information about the fault remains in the control module.
Reading off the Volvo on-board diagnostic (OBD) system
Location of Components DSA, Data Link Connector DLC:
Information about faults and other data can be read off using the VIDA PC connected to the data link connector (DLC). The VIDA PC communicates with the control module via a standardized interface.
Volvo on-board diagnostic (OBD) system
With the VIDA PC it is possible to:
- read off and erase stored diagnostic trouble codes (DTCs)
- read off and erase the status of the low current protection
- continuously monitor the values and status of the input and output signals for the signals
- activate certain functions
- program the control module with certain information
- read the control module identification.
The following conditions must be met before the Volvo on-board diagnostic (OBD) system is activated:
- the ignition must be on
- the battery voltage must be normal.
Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function. The on-board diagnostic (OBD) system can identify 25 different faults in the form of diagnostic trouble codes (DTCs).
Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once.
Read off and erase the status of the low current protection
With this option the low current protection status can be read off and erased.
The control module uses the low current protection to interrupt or shut off the additional heater while running if the control module registers that the power supply is too low.
Reading off input and output signals
Using this function, the values and status of the control module input and output signals can be continuously read off.
The following parameters can be read off:
- battery voltage, value
- outside temperature, value
- coolant temperature, value
- additional heater, status
- ignition supply, status
- generator (GEN) voltage D+, status
- the status displays whether or not the control module has registered that the power supply is too low
- fuel pump (FP), status
- glow plug, status
- water pump, status
- combustion fan, value
- timer, status
- run time, value.
Activating components and functions
With this function the components and functions in the additional heater system can be activated.
The following components can be activated:
- the additional heater
- the water pump
- the combustion fan
- the glow plug.
Note! The engine must be running in order for the additional heater to operate. When the heater is functioning as a parking heater, the heater is activated using the start / stop button on the timer when the ignition is on. The heater control unit on certain cars does not have a +15 power supply. This means that individual components and functions cannot be activated.
Reading off and programming data
With this option it is possible to read programmed data and program in data. The aim with this programming is set up the additional heater function according to the customer's requirement.
Note! If possible, read off all data from the control module before replacing the control module. After replacement, the current data must be programmed into the new control module.
The programmable data is the start temperature setting. Start temperature refers to the highest outside temperature at which the additional heater may start.
Reading off the control module identification
The control module can be identified by reading off a code from the control module memory.
This code contains information about the control module P/N